Dr. Brad Lepper, of the Ohio Historical Society Archaeological Blog, has written an interesting post about the potential significance of skulls found in some Ohio Hopewell sites.
"there are various iconic depictions of detached human heads and headless bodies in Hopewell art, but these are subject to the same alternative interpretations. A mica cut-out of a headless human torso might represent a mutilated enemy’s body or a ritually dismembered ancestor. The sculpture of a Hopewell shaman wearing bear regalia and holding a human head could depict an act of ancestor worship or some sort of ritual honoring or debasing a defeated enemy..."
For more information about this topic, Dr. Brad Lepper also has a brief column in the Columbus Dispatch from March 2nd, 2014 entitled Hopewell Skulls Pose a Mystery.